DOHA, Qatar — Anticipating an onslaught of criticism from poor nations, the United States claimed “enormous” strides in reducing greenhouse emissions at the opening of U.N. climate talks Monday, despite failing to join other industrialized nations in committing to binding cuts.

The pre-emptive U.S. approach underscores one of the major showdowns expected at the two-week conference as China pushes developed countries to take an even greater role in tackling global warming.

Speaking for a coalition of developed nations known as the G77, China’s delegate, Su Wei, said rich nations should become party to an extended Kyoto Protocol — an emissions deal for some industrialized countries that the Americans long ago rejected — or at least make “comparable mitigation commitments.”

The United States rejected Kyoto because it didn’t impose any binding commitments on major developing countries such as India and China, which is now the world’s No. 1 carbon emitter.

American delegate Jonathan Pershing offered no new sweeteners to the poor countries, only reiterating what the United States has done to tackle global warming: investing heavily in clean energy, doubling fuel efficiency standards and reducing emissions from coal-fired power plants. Pershing also said the United States would not increase its earlier commitment of cutting emissions by 17 percent below 2005 levels by 2020. It is half way to that target.

“I would suggest those who don’t follow what the U.S. is doing may not be informed of the scale and extent of the effort, but it’s enormous,” Pershing said.

“It doesn’t mean enough is being done. It’s clear the global community, and that includes us, has to do more if we are going to succeed at avoiding the damages projected in a warming world,” Pershing added. “It is not to say we haven’t acted. We have and we have acted with enormous urgency and singular purpose.”

The battles between rich and poor nations have often undermined talks in the past decade and stymied efforts to reach a deal to keep global temperatures from rising more than 2 degrees C (3.6 F), compared to preindustrial times. Efforts taken in the absence of a deal to rein in emissions, reduce deforestation and promote clean technology are not getting the job done. A recent projection by the World Bank showed temperatures are expected to increase by up to 4 degrees C (7.2 F) by 2100.

Countries are hoping to build on the momentum of last year’s talks in Durban, South Africa, where nearly 200 nations agreed to restart stalled negotiations with a deadline of 2015 to adopt a new treaty and extend Kyoto between five and eight years. The problem is that only the European Union and a handful of other nations — which together account for less than 15 percent of global emissions — are willing to commit to that.